Flask



FIG. 1 is a perspective view showing the new design for the flask.

FIG. 2 is a front view thereof.

FIG. 3 is a right side view thereof.

FIG. 4 is a left side view thereof.

FIG. 5 is a top view thereof.

FIG. 6 is a bottom view thereof; and,

FIG. 7 is a backside view thereof. 

CLAIM The ornamental design for a flask, as shown and described. 